In photographing, if the frame includes multiple shooting targets, taking multiple faces as an example, when the depth of field of the lens is relatively small, all people must be in the same focal plane, that is, all the faces need to be in the depth of field in order to make everyone's face clearly visible. When multiple faces are in different focal planes, due to the relationship of depth of field, the face in the depth of field can be photographed clearly, while the face outside the depth of field is not clearly.